Conveyer furnace



Jan. 16,1945. J. B. RAUEN CONVEYER FURNACE Filed April 19, 1943 Patented Jan. 16, 1945 UNITED STATES PATENT OFFICE CONVEYER FURNACE John B. Rauen, Los Angeles, Calif., assignor to United States Spring & Bumper 00., Los Angeles, Calif., a corporation of California Application April 19, 1943, Serial No. 483,701

6 Claims. (Cl. 263-8) This invention relates to conveyer furnaces, and more particularly to a conveyer furnace of the type utilized for continuous heat treatment of metal members.

In the heat treatment of steel arm-or plate, very exacting conditions of temperature are required in order to insure uniformity of heat treatment throughout the plate sections. In the utilization of continuous type furnaces as heretofore constructed and operated, it has been found that too great variation in the treatment resulted in producing heat treated plates, 2. large proportion of which would not pass the tests.

It is therefore an object of this invention to provide a continuous conveyer type heating furnace wherein the heating elements are so arranged as to insure equal distribution of heat.

Another object of this invention is to provide a conveyer furnace particularly applicable for the heat treating of steel armor plate wherein means are provided for maintaining uniform heating conditions over the entire area of the plates being heat treated throughout the travel of such plates through the furnace.

v Another object of this invention is to provide a conveyer type furnace provided with a supplementary heating means particularly adapted to avoid localized temperature differences within the heating tunnel.

" Another object of this invention is to provide a conveyer type furnace including a heating tunnel having positioned therein a pair of spaced conveyer means adapted to support and convey the article to be heat treated through the tunnel and in which heating means are provided for maintaining a circulation of heating gases over the surfaces of such plates including a centrally disposed heating means located below the level of the plates and acting to supplement the heat as circulated into the tunnel from the opposed sides thereof to maintain uniform temperatures over surfaces of the plates or articles being heat treated.

Other objects andadvantages of this invention it is believed will be apparent from the following detailed description of a preferred embodiment thereof as illustrated in the accompanying drawing.

In the drawing:

Figure 1 is a side elevation of a diagrammatic character of the conveyer furnace embodying my invention.

Figure 2 is a sectional view taken substantially on the line 2-2 of Figure 1.

In the preferred embodiment of my invention as illustrated in the accompanying drawing, I indicates a tunnel which may be of any suitable or desirable construction and which is usually built up of fire clay tile or brick and which is supported on a frame work 2 elevated from the floor or ground surface. The opposed ends of the tunnel are closed except for the lower ends of said end sections through which the conveyers and articles to be heat treated pass. This leaves at both ends of the tunnel a lower section open, the extent of which opening depends upon the size of the articles to be heat treated and the length of the conveyer arms supporting said articles.

In furnaces of this type as generally employed, the heat is admitted into the tunnel I from a multiplicity of points along the side walls 3. As illustrated, the heating means includes conduits 4 which are distributed along the side wall 3 in such manner as to position gas or fuel burners at the conduit ends 5 which communicate with circulation channels 6 formed through the side walls 3 and opening above the floor l of the tunnel I. Any suitable or desirable type of burner I may be employed for the utilization of gas, oil or other heating means and as the construction of these burners is well understood in the art, I have not specifically illustrated their construction.

These burners l, as is customary in this art, are spaced at regular intervals along the side walls 3 and at varying elevations from the em trance end 8 to the exit end 9 of the tunnel l. The distribution of these burners and the channels 6 are such as to produce a uniform heat within the tunnel I above the work indicated as the armor plate sections shown at I0.

As the tunnel section must be'open to permit passage of the conveyer arms ll, cold gases or air may .pass through the conveyer arm openings indicated at l2 to a position below the armor plate I0 and, in fact, the circulation of the gases in the directions as indicated by the arrows [3 I have found tends to draw such gases into the tunnel I below the plates l0, giving rise to zones of heat irregularity within the tunnel l which prevents the uniform heating of the armored plate within the degree of accuracy required for the heat treatment of this material.

In accordance with my invention, I provide a supplemental heating means which includes a longitudinally extending fire clay channel l4 positioned centrally of the tunnel l below the position of the work or armor plate l0. This fire clay channel extends the length of the tun-- nel l and at regular spaced intervals has burner apertures 15 within which fuel burners 8 are positioned. The fuel burners 8 within these apertures are supplied with fuel through a conduit [6 so that at regular spaced intervals heat by flame is emitted from the channel I4 through the spaced apertures l5 along the floor l and into the circulating heated gases. emitted. into the tunnel I from the burners l. The effect of this treatment is to raise the temperature of the fire clay of which the channel I4 is formed. so that by both radiation and convection the heat is added to the circulation of heated gases as indicated by the arrows [3 at a position centrally disposed with reference to the spaced armor plates l0 and below the lower surfaces thereof avoiding the cooling effect occasioned by the cold gases or air passing through the conveyer arm openings 12 formed in the floor I. In this manner I have obtained a uniform heat treatment of such articles, enabling me to control accurately the heat treatment temperature within the very few degrees range of temperature difference found necessary in order to obtain the requisite heat treatment of such materials as sections of armor plate.

The armor plate is conducted through the tunnel l by any suitable form of endless conveyer as indicated at H, which conveyer carries a plurality of conveyer arms H upon which the material [0 to be heat treated is supported. The conveyer is positioned so that its upper run 18 carrying the supporting arms ll passes along the lower surface of the tunnel I while its return run I9 passes below the floor or lower surface of the tunnel. The conveyer H is driven by any suitable or desirable means at such rate as will conduct the material to be heat treated through the tunnel l for the time requisite for the heat treatment desired.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

. I claim:

1. In a conveyer furnace, the combination of. a tunnel having a roof, side walls and a floor, a conveyer adapted to support an article to be heat treated in position spaced away from the floor, heating means disposed at spaced points lengthwise of the wall and above the article to be heated, a fire clay channel positioned on the floor below the article to be heated, and havingspaced flame orifices directed laterally of the tumiel and below the article to be heated.

2. In a conveyer furnace, the combination of a tunnel, a conveyer adapted to support and convey articles to be heat treated through the tunnel, the tunnel having heating means disposed along its walls above the conveyer, and a heat dispensing channel positioned in the tunnel below the article supported on the conveyer.

3. In a conveyer furnace, the combination of a tunnel, conveyers positioned in side by side.

relation within the tunnel and adapted to support and convey articles to be heat treated through the tunnel, heating means for emitting heat into the tunnel from the side walls thereof, said heating means being located above the articles supported on the conveyer, and a heat channel positioned between the conveyers and below the articles supported thereon and adapted to supply heat [for conduction and radiation within the furnace below said articles.

4. In a conveyer furnace, the combination of a tunnel, a conveyer adapted to support articles and convey the same through the tunnel, the tunnel having primary heating means located along the side walls of the tunnel above the articles 0n the conveyer, and a supplementary heating means including a fire clay channel positioned within the tunnel below the articles supported on the conveyer and having heat discharge apertures positioned in spaced relation along its side walls whereby heat is supplied within the tunnel by conduction and radiation below the articles supported on the conveyer.

5. In a heat treatment device, the combination of a tunnel having a bottom, sides and a. roof, and, having entrance and exhaust openings at its opposed ends, a conveyer adapted to travel through the tunnel above the bottom, said conveyer being adapted to support and carry articles to be heat treated through the tunnel, fuel burners mounted along the side walls of the tunnel to supply heat within the tunnel above the conveyer, a heat channel formed within the tunnel and positioned below the article supported on the conveyer, said channel extending. longitudinally of the tunnel, the channel being formed to provide a multiplicity of laterally directed apertures, burners within the channel whereby heat is supplied within the. tunnel from said channel to supplement the first said heat burner and where said heat is supplied within the tunnel below the articles on the conveyer and is directed transversely of the tunnel.

' 6. In a heat treatment device, the combination of a tunnel having bottom, sides and a roof, and

being open. at its opposed ends, a conveyer I adapted to travel through the tunnel. above. the bottom, said conveyer being adapted to support and carry articles to be heat treatedv through the tunnel, fuel burners mounted along the side walls of the tunnel within circulation channels formed through the side walls, a heat channel formed within the tunnel below the articles. supported. on the conveyer, said channels having a plurality of laterally directed apertures, heat burners mounted within the channels. to direct heat laterally of the tunnel and to supplement the heat provided from the first said burners and. to maintain the heat circulation within the tunnel below the articles. upon the. conveyer-and through the side wall channels to the first said burners- JOHN B. RAUEN. 

